Friday, November 03, 2006

End of the (Fishing) Line

The world will run out of seafood by 2048 if steep declines in marine species continue at current rates, according to a study released today by an international group of ecologists and economists.

The paper, published in the journal Science, concludes that overfishing, pollution, and other environmental factors are wiping out important species across the globe, hampering the ocean's ability to produce seafood, filter nutrients and resist the spread of disease.

"We really see the end of the line now," said lead author Boris Worm, a marine biologist at Canada's Dalhousie University. "It's within our lifetime. Our children will see a world without seafood if we don't change things."

Historical records from coastal zones in North America, Europe and Australia also show declining yields, in step with declining species diversity; these are yields not just of fish, but of other kinds of seafood too.

Zones of biodiversity loss also tended to see more beach closures, more blooms of potentially harmful algae, and more coastal flooding.

Experiments performed in small, relatively contained ecosystems show that reductions in diversity tend to bring reductions in the size and robustness of local fish stocks. This implies that loss of biodiversity is driving the declines in fish stocks seen in the large-scale studies.

The final part of the jigsaw is data from areas where fishing has been banned or heavily restricted.

These show that protection brings back biodiversity within the zone, and restores populations of fish just outside.

"The good news is that it is not too late to turn things around," Worm said. The scientists studied 48 areas worldwide that have been protected to improve marine biodiversity. "We see that diversity of species recovered dramatically, and with it the ecosystem's productivity and stability."

"Through this research, it became clear to me that we hardly appreciate living on a blue planet," Worm said. "The oceans define our planet, and their fate may to a large extent determine our fate, now and in the future."